Additive manufacturing (AM) is a technique for fabricating a desired object through a process of adding a material based on three-dimensional (3D) geometric data, and is the opposite of traditional manufacturing processes such as subtractive manufacturing. It is commonly carried out by adding layer-upon-layer of material and is also referred to as additive fabrication, additive processes, an additive technique, or additive layer manufacturing. 3D printers were initially used for industrial purposes in the late 1980s in line with the development of computers that enabled the production of 3D miniatures or prototypes based on computer aided drawing (CAD) data in a short time at inexpensive prices, and have been widely used as a way of rapid prototyping (RP), mostly in product design and validation phases. Compared to other conventional manufacturing processes, AM is known to reduce about 50% or more of the energy and about 90% or more of the materials spent on the production. Because of such benefits that the technique offers, AM is widely used in various fields including the industrial fields of automotive, aerospace, construction, and household appliances, including manufacturers such as Siemens, BMW, Volkswagen, GM, NASA, GE, BOSE, HP, and the like.
Above all, a powder bed and inkjet head 3D printing technique is a method of accumulating layers by uniformly spreading a powder material into a thickness of several hundred micrometers (μm) and spraying an adhesive thereon with an inkjet printer to induce adhesion in desired areas only. The powder material in the areas to which the adhesive was not sprayed is removed by pneumatic pressure to finally obtain a desired 3D shape, and the final 3D structure is normally attained through a second curing process using an adsorbent. However, the structure attained by the spraying of an adhesive may be dried by heat treatment before removing the powder, which is a widely used method despite a rather low precision level (usually 100 μm or less) compared to other additive manufacturing techniques, because the method enables the recycling of the powder material and the easy manufacturing of even a 3D structure suspended in midair. In particular, since the formation of various functional materials possible would be made possible, should various functional materials and adhesives in powder forms be developed, there is a growing interest for the powder bed and inkjet head 3D printing technique among numerous additive manufacturing techniques.
A number of papers and patent documents are referenced and the citations thereof are displayed throughout the present specification. The disclosures of the cited papers and patent documents are incorporated herein by reference in their entirety to describe the level of the art and the contents of the present invention more clearly.